As you can see I have two examples one with simple password and one with encrypted password. You can use password variable for basic use, as used for default account in .msmtprc file. If you don’t want your friends to see your password, who use your computer, and more specifically your user, then you should definately use passwordeval variable. passwordeval variable tells the msmtp to fetch password from an encryped gpg file. More details on Encrypting password in with GnuPG, of course you need to see what you want from that link.